Where cancer can spread

This page tells you about where cancers can spread. There is information about

Places cancers can spread to

Cells can break away from a cancer and spread in the blood or lymph systems to almost anywhere in the body. But most types of cancer tend to spread most often to one or two places. 

Where cancer can spread diagram

You can read about how cancer can spread.

The lungs

The lungs are the most common organ for cancers to spread to. This is because the blood from most parts of the body flows back to the heart and then to the lungs before it goes to any other organ. Cancer cells that have found their way into the bloodstream can get stuck in the tiny blood capillaries of the lungs.

Cancer that has spread to the lungs may not cause any symptoms or it may cause

  • A cough that doesn't go away
  • Shortness of breath
  • Chest infections
  • A build up of fluid between the chest wall and the lung called a pleural effusion – this in turn causes shortness of breath, chest aching, discomfort and heaviness

Diagram showing a build up of fluid in the lining of the lungs

Fluid builds up because cancer cells cause inflammation of the pleura (also called the pleural membrane). The pleura are the two sheets of tissue that cover the lungs. The inflamed tissues make extra fluid and the fluid collects between them. There may also be cancer cells in the pleural space that stop the extra fluid draining away. The lungs expand (inflate) as we breathe in. This fluid build up gets in their way and presses on the lungs, stopping them from expanding fully.

The treatment for cancer that has spread (secondary cancer) depends on where the cancer started in the body (the primary cancer). So breast cancer that has spread to the lungs will be treated like a breast cancer, not like lung cancer.

You can read about treatment to drain fluid on the lung.

The liver

Many types of cancer can spread to the liver. It is most likely to occur with cancers of the digestive system because the blood from the digestive system circulates through the liver before it goes back to the heart. The cancer cells get stuck in tiny capillaries of the liver.

Cancer that has spread to the liver may not cause any symptoms. But it may cause

  • A lack of energy
  • Feeling generally unwell
  • Feeling sick
  • Lack of appetite
  • Discomfort on the right side of the body under the rib cage
  • Jaundice
  • A build up of fluid in the abdomen

Jaundice is the medical name for a build up of bile salts in the blood. This usually happens when the bile ducts in the liver are blocked. The build up of bile salts makes the skin and whites of the eyes turn yellow. It can also make the skin become itchy. The urine often looks very dark and bowel motions can look pale.

Ascites is the name for a build up of fluid in the abdomen. It forms if the cancer blocks the normal blood flow through the liver and causes a back pressure of fluid. The healthy liver also makes proteins that circulate in the blood. The proteins help to keep fluid in the blood and stop it from leaking out into the tissues. If the liver is damaged, it may not make enough of these proteins and so fluid can leak out and collect in the abdomen or in other parts of the body, such as the feet and ankles.

Diagram showing fluid in the abdomen

You can read about fluid in the abdomen and its treatment.

The lymph nodes

It is very common for cancer cells to travel from the area of the original cancer to nearby lymph nodes. This is because there is a natural circulation of tissue fluid from the organs into the lymphatic system. This is not the same as having a cancer of the lymphatic system, such as lymphoma.

If cancer spreads to the lymph nodes it may make them swell up. The swollen lymph nodes are easy to see if they are near the surface of the body – for example, in the neck or under the arm. But if the nodes are deeper in the body, they can only be seen on a scan.

Cancer in the lymph nodes may not cause any symptoms. But sometimes, the swollen lymph nodes can block the circulation of tissue fluid. This can cause swelling in the affected part of the body. For example, swollen lymph nodes in the armpit or groin can cause swelling in the arm or leg on the same side of the body. This swelling is called lymphoedema. 

You can read detailed information about lymphoedema.

The bones

Some cancers are quite likely to spread to the bones – for example, prostate cancer, breast cancer and lung cancer. 

The most common effects of secondary cancer in the bones are

  • Pain in the affected bones
  • Weakness in the affected bones
  • Raised calcium levels in the blood

Pain occurs because the cancer cells multiply in the bone and press on nerves. The growing cancer can weaken the bone by damaging its normal structure. This may mean that it is more likely to break. If this happens it is called a pathological fracture. 

You can find out about secondary bone cancers and their treatment.

Damaged bone cells can release calcium into the blood. If high calcium levels build up in the blood you may

  • Feel sick
  • Feel tired, drowsy or muddled
  • Become constipated
  • Feel very thirsty

If the calcium levels become very high they can cause irritability and confusion and eventually unconsciousness. 

We have information about cancer and high blood calcium levels.

The brain

Some types of cancer can spread to the brain, such as lung cancer and breast cancer. More rarely colon (bowel) cancer, kidney cancer and melanoma can spread to the brain.

The most common symptoms are headaches and feeling sick. These symptoms are caused by the growing cancer taking up space. The space for the brain is limited by the skull so the growing cancer causes an increase in pressure inside the skull. This is called raised intracranial pressure.

Other symptoms depend on which part of the brain the cancer is growing in. They also depend on the size of the tumour (or tumours). Small secondary brain tumours may not cause symptoms. If symptoms occur they may include any of the following

  • Weakness in an arm, leg, or on one side of the body
  • Moodiness or changes in behaviour
  • Fits (seizures)
  • Confusion
  • Drowsiness
  • A feeling of the room spinning (vertigo) 
  • Feeling dizzy or unsteady

You can read about secondary brain tumours and their treatment.

The skin

Sometimes cancer cells can start growing in the skin. The secondary skin cancer may start to grow on or near an operation scar where the primary cancer was removed. Or sometimes secondary skin cancers can grow in other parts of the body.

A secondary skin cancer may look like a pink or red raised lump (a bit like a boil). Doctors may call these areas plaques or nodules. Secondary skin cancers can be treated. It is important to tell your doctor if you think you have one. Without treatment the area may become bigger and may bleed or ooze fluid. This is called an ulcerating cancer.

You can read about ulcerating cancer.

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